Development of Anisotropic Magnetized Viscosity for Magnetized Liner Inertial Fusion Simulations in FLASH

TL;DR

This paper introduces the first implementation of the full Braginskii magnetized viscosity tensor in FLASH for MagLIF simulations, revealing its significant effects on implosion dynamics and stability.

Contribution

It provides a validated, comprehensive implementation of magnetized viscosity effects in MagLIF simulations within FLASH, enabling more accurate modeling of magnetized plasma behavior.

Findings

Magnetized viscosity damps vortical structures in simulations.

It converts kinetic energy into thermal energy, affecting plasma heating.

Including magnetized viscosity helps preserve yield in perturbed simulations.

Abstract

Magnetized liner inertial fusion (MagLIF) operates in a regime where anisotropic transport phenomena fundamentally influence implosion dynamics. In strongly magnetized plasmas, the viscous stress tensor becomes highly anisotropic, yet no prior work has incorporated or examined magnetized viscosity effects in MagLIF configurations. We present the first implementation of the full Braginskii magnetized viscosity tensor for arbitrary magnetic field orientations in the Pacific Fusion branch of FLASH. The implementation is verified through analytical comparisons, direct verification against Braginskii's original formulation, Method of Manufactured Solutions, and against analytical shock solutions. Application to MagLIF-relevant configurations reveals that magnetized viscosity damps vortical structures, converts kinetic energy in those vortical structures into thermal energy, and mitigates the Rayleigh-Taylor instabilities. Simulations with seeded perturbations demonstrate yield preservation when magnetized viscosity is included. These results establish magnetized viscosity as a non-negligible physical mechanism in MagLIF plasmas and provide a validated capability for predictive modeling of magnetized high-energy-density plasmas.